Ms Symes will tell MPs next week that the impact of the 100ft underground tunnel linking East and West London has not undergone a thorough Environmental Impact Assessment. She believes that it is an oversight to route it under the Grade II* listed building housing the Museum of Immigration and Diversity, as Transport for London propose to do.

“This is a major, major scheme costing billions of pounds,” said Ms Symes, “but, to put it bluntly, they simply haven’t done their assessmentproperly. They have no idea of the structure of this building.”

The rail tunnel would travel directly under 19 Princelet Street, home of Huguenot silk weavers in the 18th century. Jewish immigrants from Eastern Europe later built a synagogue in the garden, and the museum now celebrates the multicultural heritage of the building and British Society. The building is already in a fragile state of repair due to its age and lack of funds, and is on the English Heritage ‘At Risk’ register.

Ms Symes is concerned that the tunnel would lead to settling of the 1719 building, which could make it unsound. Given its important educational role and international significance, she argues, it should not be put in any further danger.

“This is the only listed building in Britain that deals with immigration and multicultural issues,” she said, “and it’s in the middle of an area of great cultural diversity, which means they need to carry out a further impact assessment – which they didn’t know about. It’s completely inadequate.”

The museum only opens to the public on certain days throughout the year because of its condition, while the campaign for funds to pay for work is ongoing.

“This is a national treasure, unique in Europe,” said Ms Symes. “The museum brings in educational groups from all over the world – we’ve just had schools visiting from Denmark and Germany, American college students … London should be proud of it, but Crossrail were totally unaware of the existence of the work that we do here.”

An additional worry is that no compensation would be payable to the charitable trust that runs the museum if it should fall into further disrepair after the building of the tunnel, because it is already in delicate order.

Ms Symes will urge the Commons Select Committee on the Crossrail Bill to go with one of the alternative routes, either further north under a disused brewery scheduled for demolition or closer to the river.

Transport for London denies that the museum will suffer. “The museum will not be affected by the work nor damaged by the tunnelling which will be more than 100ft below ground,” said a spokesman.

“Why put historic buildings at risk?” asked Ms Symes. “There are alternative routes. Why put something important – a multicultural community and an educational service – at risk, when there are two other routes that don’t have this problem?”

The Museum of Immigration and Diversity will be open to the public, free of charge, for Refugee Week, June 18-25 2006 12pm-7pm, and thereafter by appointment until further scheduled openings.